458 American was a wildcat developed in 1962 by Frank C. Barnes. Otherwise known as the 458 X 2 inch. Most wildcats are developed by moving the shoulders forward to increase the powder capacity therefore increasing velocity. Frank Barnes did the exact opposite. Taking the 458 Winchester Magnum case and shortening by one half of an inch, thereby creating a cartridge more suited to North American game. Using the still very strong H&H; magnum case as a basis, well suited to short magnum actions. He wanted a short to moderate range stopping rifle for pursuing big game in close cover, such as bear or also well suited for moose. In other words game bigger than,or tougher than, deer.Its large bore is perfect for bullets of 300 grains or higher in weight. This cartridge has also gained some following in American states for hunting very fast and potentially dangerous wild boar/feral pigs. 

This text is based on information from “Cartridges of the World”, Hodgdon reloading manual, the cartridge designer and/or own resources.